The present invention relates to containers for liquid inhalation anesthetics, more particularly, to aluminum containers that are suitable for storing halogenated inhalation anesthetics.
Containers, such as those of the present invention, are used to store the liquid anesthetic agent, and to dispense it to a device for administering the agent to a patient. These devices are known in the art as “vaporizers’, which mate with the container, receive the liquid anesthetic through an orifice in the container, vaporize the anesthetic, mix it with oxygen and optionally other gases, and mete out the gaseous mixture to the patient.
Inhalation anesthetics have traditionally been stored in glass containers. These containers, however, possess certain drawbacks. Glass requires careful handling to avoid breakage, and when breakage does occur, product is lost and injury may occur. In addition, it has been theorized that the inhalation anesthetic may react with components of the glass, leading to certain degradation products. C.f. U.S. Pat. No. 5,990,176.
A number of patents have taught the use of plastic containers for inhalation anesthetics and, in particular, sevoflurane. For example, U.S. Pat. No. 4,250,334 teaches the use of “Kel-F” plastic for a container for holding sevoflurane. “Kel-F” is understood to be the trade name for chlorotrifluoroethylene. U.S. Pat. No. 5,679,576 teaches the use of a container lined with PTFE, or polytetrafluoroethylene, for holding sevoflurane. U.S. Pat. No. 5,505,236, teaches the use of a plastic container with an inhalation anesthetic. While not specifically naming the inhalation anesthetic, it is believed that the commercial embodiment of the system shown in the '236 patent has been used with the anesthetic sevoflurane. Despite the existence of these patents teaching plastic containers to hold sevoflurane, a number of additional patents have recently issued that have taught the use of particular types of plastic for containers to hold sevoflurane. See, e.g., U.S. Pat. No. 6,074,668 (polyethylene napthalate), U.S. Pat. No. 6,083,514 (polymethylpentene) and U.S. Pat. No. 6,162,443 (polypropylene, polyethylene and ionomeric resins). The present invention presents an alternative type of container (aluminum) to hold sevoflurane.
In addition, containers for inhalation anesthetics made of certain plastics have been proposed. C.f. WO 99/34762, U.S. Pat. Nos. 6,074,668 and 6,162,443 and U.S. Patent Application Publication No. U.S. 2001/0000729 A1. While plastic containers are less likely to break than glass containers, they are still susceptible to breakage under common use conditions. Moreover, many plastics tend to be vapor permeable, allowing the inhalation anesthetic to escape the container and ambient vapors to enter the container over time, leading to possible contamination. Also, plastic containers are subject to deformation when exposed to elevated temperatures, which may be required during processing and treatment of the inhalation anesthetic-containing containers. Moreover, inhalation anesthetics have strong organic solvent properties, which typically will dissolve and/or react with the plastic material, leading to measurable impurities in the inhalation anesthetic.
Containers for sevoflurane have also been made of stainless steel. For example, U.S. Pat. No. 5,990,176 describes a container made of glass, plastic or stainless steel for holding sevoflurane. Metal containers have been used for various types of pharmaceutical products, as well as food and beverages. U.S. Pat. No. 6,008,273 describes an epoxy resin for coating the inside of a metal container for use as a food or beverage container.